I. Technical Field
The present invention relates to a rolling bearing, which can be applied to, for example, a roller bearing used for a shaft supporting portion as a transmission of an automobile.
II. Description of the Related Art
JP-A-02-168021 and JP-A-06-42536 each disclose a rolling bearing in which a surface of a rolling element is provided with minute irregularities formed thereon to improve an oil film forming ability. In this conventional technique, as a countermeasure for a damage due to poor lubrication, such as a peeling damage of a roller bearing, there are provided recesses each having a minute concave shape in rolling contact surfaces of rollers and/or raceway surfaces of inner and outer races. When the surface roughness is expressed by a parameter Rqni, a value of a ratio Rqni(C)/Rqni(C) between an axial surface roughness Rqni(L) and a circumferential surface roughness Rqni(C) becomes 1.0 or less, and a parameter Sk value of the surface roughness is set to be −1.6 or less, thereby elongating a life of the rolling bearing if a mating surface is either a rough surface or a smooth-finished surface.